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#pragma once
#include "clickhouse_config.h"
#if USE_RAPIDJSON
# include <base/types.h>
# include <base/defines.h>
# include <rapidjson/document.h>
# include "ElementTypes.h"
namespace DB
{
/// This class can be used as an argument for the template class FunctionJSON.
/// It provides ability to parse JSONs using rapidjson library.
struct RapidJSONParser
{
class Array;
class Object;
/// References an element in a JSON document, representing a JSON null, boolean, string, number,
/// array or object.
class Element
{
public:
ALWAYS_INLINE Element() = default;
ALWAYS_INLINE Element(const rapidjson::Value & value_) : ptr(&value_) {} /// NOLINT
ALWAYS_INLINE ElementType type() const
{
switch (ptr->GetType())
{
case rapidjson::kNumberType: return ptr->IsDouble() ? ElementType::DOUBLE : (ptr->IsUint64() ? ElementType::UINT64 : ElementType::INT64);
case rapidjson::kStringType: return ElementType::STRING;
case rapidjson::kArrayType: return ElementType::ARRAY;
case rapidjson::kObjectType: return ElementType::OBJECT;
case rapidjson::kTrueType: return ElementType::BOOL;
case rapidjson::kFalseType: return ElementType::BOOL;
case rapidjson::kNullType: return ElementType::NULL_VALUE;
}
}
ALWAYS_INLINE bool isInt64() const { return ptr->IsInt64(); }
ALWAYS_INLINE bool isUInt64() const { return ptr->IsUint64(); }
ALWAYS_INLINE bool isDouble() const { return ptr->IsDouble(); }
ALWAYS_INLINE bool isString() const { return ptr->IsString(); }
ALWAYS_INLINE bool isArray() const { return ptr->IsArray(); }
ALWAYS_INLINE bool isObject() const { return ptr->IsObject(); }
ALWAYS_INLINE bool isBool() const { return ptr->IsBool(); }
ALWAYS_INLINE bool isNull() const { return ptr->IsNull(); }
ALWAYS_INLINE Int64 getInt64() const { return ptr->GetInt64(); }
ALWAYS_INLINE UInt64 getUInt64() const { return ptr->GetUint64(); }
ALWAYS_INLINE double getDouble() const { return ptr->GetDouble(); }
ALWAYS_INLINE bool getBool() const { return ptr->GetBool(); }
ALWAYS_INLINE std::string_view getString() const { return {ptr->GetString(), ptr->GetStringLength()}; }
Array getArray() const;
Object getObject() const;
private:
const rapidjson::Value * ptr = nullptr;
};
/// References an array in a JSON document.
class Array
{
public:
class Iterator
{
public:
ALWAYS_INLINE Iterator(const rapidjson::Value::ConstValueIterator & it_) : it(it_) {} /// NOLINT
ALWAYS_INLINE Element operator*() const { return *it; } /// NOLINT
ALWAYS_INLINE Iterator & operator ++() { ++it; return *this; }
ALWAYS_INLINE Iterator operator ++(int) { auto res = *this; ++it; return res; } /// NOLINT
ALWAYS_INLINE friend bool operator ==(const Iterator & left, const Iterator & right) { return left.it == right.it; }
ALWAYS_INLINE friend bool operator !=(const Iterator & left, const Iterator & right) { return !(left == right); }
private:
rapidjson::Value::ConstValueIterator it;
};
ALWAYS_INLINE Array(const rapidjson::Value & value_) : ptr(&value_) {} /// NOLINT
ALWAYS_INLINE Iterator begin() const { return ptr->Begin(); }
ALWAYS_INLINE Iterator end() const { return ptr->End(); }
ALWAYS_INLINE size_t size() const { return ptr->Size(); }
ALWAYS_INLINE Element operator[](size_t index) const { assert(index < size()); return *(ptr->Begin() + index); }
private:
const rapidjson::Value * ptr = nullptr;
};
using KeyValuePair = std::pair<std::string_view, Element>;
/// References an object in a JSON document.
class Object
{
public:
class Iterator
{
public:
ALWAYS_INLINE Iterator(const rapidjson::Value::ConstMemberIterator & it_) : it(it_) {} /// NOLINT
ALWAYS_INLINE KeyValuePair operator *() const { std::string_view key{it->name.GetString(), it->name.GetStringLength()}; return {key, it->value}; }
ALWAYS_INLINE Iterator & operator ++() { ++it; return *this; }
ALWAYS_INLINE Iterator operator ++(int) { auto res = *this; ++it; return res; } /// NOLINT
ALWAYS_INLINE friend bool operator ==(const Iterator & left, const Iterator & right) { return left.it == right.it; }
ALWAYS_INLINE friend bool operator !=(const Iterator & left, const Iterator & right) { return !(left == right); }
private:
rapidjson::Value::ConstMemberIterator it;
};
ALWAYS_INLINE Object(const rapidjson::Value & value_) : ptr(&value_) {} /// NOLINT
ALWAYS_INLINE Iterator begin() const { return ptr->MemberBegin(); }
ALWAYS_INLINE Iterator end() const { return ptr->MemberEnd(); }
ALWAYS_INLINE size_t size() const { return ptr->MemberCount(); }
bool find(std::string_view key, Element & result) const
{
auto it = ptr->FindMember(rapidjson::StringRef(key.data(), key.length()));
if (it == ptr->MemberEnd())
return false;
result = it->value;
return true;
}
/// Optional: Provides access to an object's element by index.
ALWAYS_INLINE KeyValuePair operator[](size_t index) const
{
assert (index < size());
auto it = ptr->MemberBegin() + index;
std::string_view key{it->name.GetString(), it->name.GetStringLength()};
return {key, it->value};
}
private:
const rapidjson::Value * ptr = nullptr;
};
/// Parses a JSON document, returns the reference to its root element if succeeded.
bool parse(std::string_view json, Element & result)
{
rapidjson::MemoryStream ms(json.data(), json.size());
rapidjson::EncodedInputStream<rapidjson::UTF8<>, rapidjson::MemoryStream> is(ms);
document.ParseStream(is);
if (document.HasParseError() || (ms.Tell() != json.size()))
return false;
result = document;
return true;
}
#if 0
/// Optional: Allocates memory to parse JSON documents faster.
void reserve(size_t max_size);
#endif
private:
rapidjson::Document document;
};
inline ALWAYS_INLINE RapidJSONParser::Array RapidJSONParser::Element::getArray() const
{
return *ptr;
}
inline ALWAYS_INLINE RapidJSONParser::Object RapidJSONParser::Element::getObject() const
{
return *ptr;
}
}
#endif
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